Several light emitting diodes (LEDs) and corresponding buttons, which control special functions, are typically provided at the top edge of a notebook keyboard. Alternatively, several buttons may be provided on a computer screen or a television control in an on-screen display (OSD). With the development of touch control technologies, small-size touch panels are also gradually applied to high-level products to raise the additional value of products by saving buttons as well as increasing reliability by lowering the probability of damaging buttons from excessive utilization.
FIG. 1 shows a prior art small-size display circuit 10. Buttons 1 to 7 control the emissions of LEDs D1 to D7. Resistors R1 to R7 are current-limiting resistors connected to a display controller (not shown) by a connector 12.
FIG. 2 shows another prior art small-size touch display circuit 20 that includes a contact plate 22 and a touch controller 24. The contact plate 22, coupled to the touch controller 24, provides a plurality contact points CS0 to CS5. A signal 26 grounds the touch controller 24 to the contact plate 22. The signal strength from touching effects is very weak and can be easily interfered by the environment. Conventionally, the touch controller 24, fabricated as an independent integrated circuit (IC), is needed and is provided adjacent to the contact plate 22 to prevent noise disturbance. Therefore, the small-size touch display circuit 20, formed by the contact plate 22 and the touch controller 24, needs to be implemented on an independent small-size circuit located far from other control circuit board or power board, which leads to increased manufacturing costs.
Therefore, there is a need to develop a touch control solution capable of reducing costs.